Monitoring and detection of ships and oil spills using Synthetic Aperture Radar (SAR) have received a considerable attention over the past few years, notably due to the wide area coverage, and day and night all-weather capabilities of SAR systems. Among different polarimetric SAR modes, dual-pol SAR data are widely used for monitoring large ocean and coastal areas. The degree of polarization (DoP) is a fundamental quantity characterizing a partially polarized electromagnetic field. The performance of the DoP is studied for joint ship and oil spill detection under different polarizations in hybrid/compact and linear dual-pol SAR imagery. Experiments are performed on RADARSAT-2 C-band polarimetric data sets, over San Francisco Bay, and L-band NASA/JPL UAVSAR data, covering the Deepwater Horizon oil spill in the Gulf of Mexico.